Urgent ! need one or more expressions

[yaelle]

Hello
thanks for your very useful site. However, I didn't find what I am looking for. I need a sort of "old fashioned sentence" to promise someone to keep a secret or just to promise something and not revealing it and if you do you can be doomed. Thanks
looking forward to hearing from you
Yaelle

[Tdol]

We have 'cross my heart and hope to die', which is an expression used when promising something, or do you want the full archaic stuff like 'woe betide me should I reveal your secret'. Then again, you could just say 'your secret's safe with me', but that's not old-fashioned.

[yaelle]

thank you
I knew this one is that all there is
in french we have wooden cross, iron cross if I lie I will go to hell
can it be used or is it too french ?
thanks again

[SweetMommaSue]

Hello yaelle! Welcome to the forums!

I don't know about the expressions being "too French", but I've never heard of them.

I have to agree with tdol. "Cross my heart and hope to die, stick a needle in my eye" is very common, but I don't think old-fashioned.

I like the poetic "woe betide me. . ." --that's definitely old-fashioned.